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Biomedical subjects

C Fieschi

Publications and source records attributed to C Fieschi.

At least 235 records · Page 13Linked to original sources
PubMedDate not supplied

Platelet embolism in rabbit brain.

Transient cerebral ischemia was induced in rabbits by selective infusion of arachidonic acid (0.35 mg/kg in 15 sec) into the internal carotid artery. Platelet emboli caused transient ischemia of the brain, reaching a maximum within a few seconds after injection. After embolism the EEG flattened, blood flow stopped in almost the entire injected hemisphere, cortical pH gradually fell from 7.31 +/- 0.09 to 7.05 +/- 0.10 and cortical K+ activity rose from 4.7 +/- 1.8 to 12.7 +/- 6.4 mmol/kg H2O. Complete ischemia lasted 3-5 min; then cerebral circulation was gradually restored without reactive hyperemia. Forty-five min after embolization, circulation had been resumed in almost the entire injected hemisphere, whereas metabolic changes were still disturbed. Eighty percent of the animals recovered complete neurological function and 20% showed permanent damage confirmed by histological examination after 1 week of recovery.

Animals↗
PubMedDate not supplied

Assessment of inter-observer differences in the Italian multicenter study on reversible cerebral ischemia.

A standardized protocol was used for duplicate examination by two neurologists of the clinical history and neurological signs in 55 patients with reversible cerebral ischemia. One trained examiner from each of eight clinical centres involved in the Italian Cooperative Study on reversible cerebral ischemia participated in this research. Duplicate examination were compared in order to evaluate the percentage of agreement achieved in the responses. Several discrepancies relating to either historical data or neurological signs were detected. Possible causes of this disagreement are discussed. The inter-observer differences appear to be an important problem to be faced in cooperative studies on reversible ischemic attacks. The purpose of the study was to estimate these differences in the attempt to increase the degree of agreement by repeated training sessions and discussion between the different examiners. These efforts are needed to improve the quality of clinical investigations on reversible cerebral ischemia and to increase the validity of their results.

Evaluation Studies as Topic↗
PubMedDate not supplied

Italian multicenter study on reversible cerebral ischemic attacks: VI--Prognostic factors and follow-up results.

A total of 462 patients (mean age 52 years) affected by reversible focal ischemic attacks (RIAs) were followed prospectively in 8 neurologic institutions in Italy for 4 years. All cases were evaluated with a cerebral angiography and 21% of angiograms were normal. At the end of the follow-up period the cumulated probability for death, stroke, cardiac event and new RIA was respectively 7%, 8%, 3% and 36%. The predictive value of the baseline characteristics of this series was evaluated by a multifactorial analysis which showed that RIA and stroke (specific cerebrovascular risk) were more likely to develop in patients with a history of more than one RIA and in those in whom multiple vascular territories were involved. Moreover, previous myocardial infarction, intermittent claudication, angina pectoris, time elapsed since the first attack, and duration and severity of the attack itself were independently associated with general cardiovascular risk (death, stroke and myocardial infarction). We conclude that predictive factors, and thus also pathogenetic mechanisms, may be different for general cardiovascular risk and specific cerebrovascular risk in RIA patients.

Adult↗
PubMedDate not supplied

Animal model of TIA: an experimental study with intracarotid ADP infusion in rabbits.

Adenosine diphosphate (8 mg per minute for five minutes) was infused into the carotid artery of 63 rabbits. The effects were twofold: systemic hypotension and platelet aggregation in the cerebral circulation. As a consequence of the last effect, platelet emboli were produced which occluded cerebral arteries in a number and size sufficient to cause cerebral ischemia. Areas of focal ischemia were observed through a cranial window, and documented with antipyrine autoradiography. Platelet thrombi were almost entirely transient, being fragmented and removed within a very short time of cessation of ADP infusion. Consequently, no permanent tissue damage ensued. This experimental model approaches the spontaneous transient ischemia attacks (TIAs) in man, demonstrating that these can be caused by pure platelet emboli. A high cholesterol diet administered for two months prior to ADP infusion did not enhance the effect of the procedure or make the platelet aggregation and the following ischemia longer in duration or more severe.

Adenosine Diphosphate↗
PubMedDate not supplied

Relationship between bladder dysfunction and brain MRI in multiple sclerosis.

We studied 70 consecutive patients with definite multiple sclerosis (MS) to examine the relationship between magnetic resonance imaging (MRI) cerebral findings and urinary disturbances. Thirty-two subjects (46%) had urinary symptoms and 38 (54%) were asymptomatic. Patients with urinary symptoms exhibited greater overall functional disability. A significant correlation between the presence of midbrain lesions and urinary dysfunctions was found which may indicate an important role of the mesencephalic formation to preserve continence.

Adolescent↗
PubMedDate not supplied

Early angiographic and CT findings in patients with hemorrhagic infarction in the distribution of the middle cerebral artery.

Hemorrhagic infarction subsequent to ischemic brain damage, even if small, slight, or marbled, can be detected by CT. The mechanisms that give rise to this transformation in humans are not well elucidated. Previous reports indicate that hemorrhagic infarction is most common in embolic stroke and large infarcts, and can worsen the clinical state of ischemic patients. We examined 36 patients with supratentorial ischemic signs and symptoms within the first hours after onset. CT was used to judge if hypodensity on early CT studies might predict the development of hemorrhagic infarction. Angiography was used to observe the site of arterial occlusion, the state of collateral circulation, and the mechanisms of late reperfusion. Hemorrhagic infarction was present in 18 of our 36 patients. Angiography revealed occlusion of the middle cerebral artery or internal carotid artery (three cases) in all patients. Hypodensity was present on early CT studies in all of the 18 patients who developed hemorrhagic infarction. The finding of hypodensity on CT studies performed soon after embolic ischemic stroke is strongly predictive of hemorrhagic transformation.

Brain Ischemia↗
PubMedDate not supplied

Correlation of angiographic and sequential CT findings in patients with evolving cerebral infarction.

The usefulness of CT and angiography for predicting the final ischemic brain damage resulting from supratentorial ischemic stroke was evaluated in 36 patients. CT was performed within 4 hr and angiography within 6 hr after the onset of symptoms. CT was used to assess the site and size of parenchymal brain damage and angiography was used to evaluate the cerebral circulation. A 3-month follow-up CT study was used to determine the site and size of final ischemic damage. Angiography was normal in six patients and showed complete occlusion in 30. Angiographic findings in patients with arterial occlusion were classified as either internal carotid artery occlusion or middle cerebral artery (MCA) occlusion. MCA occlusions were subdivided into occlusion before the origin of internal lenticulostriate arteries (type 1), occlusion beyond the origin of these branches (type 2), occlusion at the bifurcation of the main trunk (type 3), and occlusion of the peripheral branches (type 4). Collateral blood supply was also studied. Early CT findings were positive in 25 of 36 patients; the lentiform nucleus alone, the lentiform nucleus and the cortex, or only the cortex were involved. In all patients with positive early CT findings, angiography showed an arterial occlusion, often located in the main trunk of the MCA. Involvement of the lentiform nucleus on early CT was always seen in patients with internal carotid artery or type 1 MCA occlusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMedDate not supplied

Echodensitometry: a methodologic approach to the non-invasive diagnosis of carotid atherosclerotic plaques.

The ultrasound image of the fibroatheromatous plaque has to date been unable to reveal the presence or absence of complications as shown by histology, such as thrombosis and intraplaque hemorrhage. We propose a novel densitometric method for determining the composition of the plaque at the echotomography, along with a new classification based on mathematical models drawn from the optical density distribution curve. This approach avails of an extremely high sensitivity. Percent areas occupied by thrombosis, intraplaque hemorrhage and atheroma in histologic sections have been shown to correspond to hyporeflecting areas in echotomographic images, whereas those occupied by calcium and fibrous tissue correspond to reflecting areas with or without acoustic shadow, respectively. This method may prove to have an important role in the non-invasive monitoring of even slight changes during progression or regression of the fibroatheromatous plaque.

Arteriosclerosis↗
PubMedDate not supplied

Evolution and severity markers in 233 MS patients.

Clinical data of 233 patients (202 definite and 31 probable MS) have been examined in relation to the following prognostic indicators: sex, age at onset, poussè frequency, interval between the first two relapses, initial symptomatology. Regression analysis technique and covariate analysis have been used versus the latest Expanded Disability Status Scale of each patients. Onset at younger age and a longer interval between the first two episodes have resulted statistically significant for a more favourable prognosis. The shift from a remitting toward a progressive course appears to happen within the first five years in 60% of the cases.

Adult↗